Search Results (51)

Background: Cisplatin, a widely used chemotherapeutic agent, is associated with significant ototoxicity, leading to progressive and irreversible sensorineural hearing loss in up to 93% of patients. Cisplatin generates reactive oxygen species (ROS) in the cochlea, activating apoptotic and necroptotic pathways that result in hair cell death. Inflammatory processes and nitrative stress also contribute to cochlear damage. Methods: This literature review was conducted to explore the mechanisms underlying cisplatin-induced ototoxicity and evaluate protective strategies, including both current and emerging approaches. A structured search was performed in multiple scientific databases, including PubMed and ScienceDirect, for articles published up to November 2024. Results: Current otoprotective strategies include systemic interventions such as antioxidants, anti-inflammatory agents, and apoptosis inhibitors, as well as localized delivery methods like intratympanic injection and nanoparticle-based systems. However, these approaches have limitations, including potential interference with cisplatin’s antitumor efficacy and systemic side effects. Emerging strategies focus on genetic and biomarker-based risk stratification, novel otoprotective agents targeting alternative pathways, and combination therapies. Repurposed drugs like pravastatin also show promise in reducing cisplatin-induced ototoxicity. Conclusions: Despite these advancements, significant research gaps remain in translating preclinical findings to clinical applications and developing selective otoprotective agents that do not compromise cisplatin’s efficacy. This review examines the mechanisms of cisplatin-induced ototoxicity, current otoprotective strategies, and emerging approaches to mitigate this adverse effect. Full article

Mitochondrial diseases are complex disorders caused by nuclear or mitochondrial DNA mutations, leading to oxidative phosphorylation deficiency and excessive production of reactive oxygen species (ROS). While ROS have been well established in the pathogenesis of these diseases, the role of reactive nitrogen species (RNS) remains unclear. In this study, we performed a quantitative analysis of muscle fibers to investigate the relationship between protein nitration and mitochondrial abnormalities (mitochondrial proliferation and cytochrome-c oxidase (COX) deficiency) and factors like genotype, muscle damage, and age. A total of 1961 muscle fibers (303 from 4 controls and 1658 from 29 patients with mitochondrial diseases) were analyzed by immunostaining for nitro-tyrosine. Contrary to previous findings, which identified nitro-tyrosine only in small muscle vessels, we observed a broader distribution affecting the sarcolemma and sarcoplasm. Using multivariate techniques, we identified a significant correlation between protein nitration and mitochondrial proliferation but found no associations with COX deficiency, age, muscle damage, or genotype. These findings suggest that nitrative stress may contribute to mitochondrial dysfunction or play a role in signaling processes that induce mitochondrial biogenesis. Our results provide new insights into the molecular mechanisms of mitochondrial diseases and highlight the potential relevance of protein nitration. Full article

Vanillic acid (VA) is a dietary benzoic acid derivative, flavoring agent, and food stabilizer. In this study, the antioxidant and anti-inflammatory potential of VA was explored in vitro and ex vivo in human immune cells and non-cellular models. In neutrophils, VA significantly downregulated the fMLP-induced oxidative burst and the generation of reactive oxygen species (ROS); it also suppressed the release of pro-inflammatory cytokines (TNF-α, IL-8) and the tissue-remodeling enzyme elastase-2 (ELA-2) in cells stimulated with LPS and fMLP+cytochalasin B. Additionally, VA showed good biocompatibility with human neutrophils and peripheral blood mononuclear cells (PBMCs) across the tested concentrations of 1–50 µg/mL. Furthermore, VA at 1–5 μg/mL enhanced the non-enzymatic antioxidant capacity of human plasma (NEAC) and prevented oxidative and nitrative damage to plasma proteins by protecting tyrosine moieties and thiols from peroxynitrite. VA also inhibited lipid peroxidation and the formation of thiobarbituric acid-reactive substances (at 50 μg/mL) and protein-bound carbonyls (at 5–50 μg/mL) in peroxynitrite-treated plasma. In non-cellular tests, VA acted as a hypochlorous acid and hydrogen peroxide scavenger and inhibited non-enzymatic protein glycation, outperforming the references Trolox and aminoguanidine. Along with existing data from animal models and studies on polyphenol intake, these results might support the synergic role of VA in dietary protection against chronic diseases related to oxidative stress and inflammation. Full article

Background/Objectives: Both hyperandrogenism (HA) and vitamin D deficiency (VDD) can separately lead to impaired vascular reactivity and ovulatory dysfunction in fertile females. The aim was to examine the early interactions of these states in a rat model of PCOS. Methods: Four-week-old adolescent female rats were divided into four groups: vitamin D (VD)-supplemented (n = 12); VD-supplemented and testosterone-treated (n = 12); VDD- (n = 11) and VDD-and-testosterone-treated (n = 11). Animals underwent transdermal testosterone treatment for 8 weeks. Target VD levels were achieved with oral VD supplementation and a VD-free diet. Estrous cycles were followed by vaginal smear, and quantitative histomorphometric measurements of the ovaries were also taken. In the 8th week, testosterone- and estrogen-induced relaxation of coronary arterioles was examined with pressure angiography. Estrogen receptor (ER) density and oxidative and nitrative stress parameters (Poly-(ADP-Ribose)-Polymerase and 3-nitrotyrosine) in the vessel wall were investigated with immunohistochemistry. Results: VDD caused impaired estrous cycles, and testosterone caused anovulatory cycles (the cycles were stopped at the diestrous phase). VDD combined with testosterone treatment resulted in reduced testosterone and estrogen vasorelaxation, lower ER density, and higher oxidative and nitrative stress in the vessel wall. Conclusions: PCOS with vitamin D deficiency may be associated with increased oxidative–nitrative stress in coronary arterioles. This oxidative and nitrative stress, potentially caused by hyperandrogenism and/or vitamin D deficiency, could impair estrogen-induced relaxation of the coronary arterioles, possibly by decreasing NO bioavailability and disrupting the estrogen-induced relaxation pathway. Full article

Background/Objectives: 6-Shogaol is a comparatively innovative anti-Parkinson’s remedy with antioxidant and anti-inflammatory characteristics. This investigation intended to determine the role of 6-shogaol in the Parkinson’s disease (PD) paradigm in rotenone-induced rats. Methods: Thirty male Wistar rats (10–12 weeks old; 180 ± 20 g) were divided into five groups. Animals with rotenone-induced experimental PD were subsequently treated with 6-shogaol-10 at 20 mg/kg for 28 days. After the experimental duration, behavioural investigations were performed, i.e., open field test, forced swim test, rotarod test, and catalepsy test. Biochemical assessments like AChE, GSH, CAT, SOD, MDA, nitrite, ceruloplasmin, proinflammatory markers such as IL-1β, NF-κB, TNF-α, and catecholamines markers (DA, GABA, and MAO-B) were determined. The docking procedure was conducted using the AutoDock Vina docking protocol. Furthermore, histopathology was performed. Results: Rotenone significantly increased the level of MAO-B, oxidative, nitrative, and pro-inflammatory markers. However, there was a decline in ceruloplasmin, dopamine, and endogenous antioxidants. Treatment with 6-shogaol (10 and 20 mg/kg) considerably sustained the elevation of oxidative stress and inflammatory indicators and decreased AChE activity and dopamine levels. In the histology of the brain, 6-shogaol improved the neuronal structure and reduced the degeneration of neurons. Based on the binding energy values, compound 6-shogaol demonstrates a favourable binding affinity to AChE, MAO-B, DA, and GABA with respective binding energies of −8.214, −8.133, −7.396 and −6.189 kcal/mol. Conclusions: In this study, 6-shogaol exhibited neuroprotective properties against PD, which could be employed as a prospective medication for PD. Full article

Compared to pathogens Pseudomonas aeruginosa and P. putida, P. donghuensis HYS has stronger virulence towards Caenorhabditis elegans. However, the underlying mechanisms haven’t been fully understood. The heme synthesis system is essential for Pseudomonas virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and Pseudomonas virulence were barely pursued. In this study, we hypothesized that hemN2 deficiency affected 7-hydroxytropolone (7-HT) biosynthesis and redox levels, thereby reducing bacterial virulence. There are four hemN genes in P. donghuensis HYS, and we reported for the first time that deletion of hemN2 significantly reduced the virulence of HYS towards C. elegans, whereas the reduction in virulence by the other three genes was not significant. Interestingly, hemN2 deletion significantly reduced colonization of P. donghuensis HYS in the gut of C. elegans. Further studies showed that HemN2 was regulated by GacS and participated in the virulence of P. donghuensis HYS towards C. elegans by mediating the synthesis of the virulence factor 7-HT. In addition, HemN2 and GacS regulated the virulence of P. donghuensis HYS by affecting antioxidant capacity and nitrative stress. In short, the findings that HemN2 was regulated by the Gac system and that it was involved in bacterial virulence via regulating 7-HT synthesis and redox levels were reported for the first time. These insights may enlighten further understanding of HemN-based virulence in the genus Pseudomonas. Full article

Visual loss in acute optic neuritis is typically attributed to axonal conduction block due to inflammatory demyelination, but the mechanisms remain unclear. Recent research has highlighted tissue hypoxia as an important cause of neurological deficits and tissue damage in both multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) and, here, we examine whether the optic nerves are hypoxic in experimental optic neuritis induced in Dark Agouti rats. At both the first and second peaks of disease expression, inflamed optic nerves labelled significantly for tissue hypoxia (namely, positive for hypoxia inducible factor-1α (HIF1α) and intravenously administered pimonidazole). Acutely inflamed nerves were also labelled significantly for innate markers of oxidative and nitrative stress and damage, including superoxide, nitric oxide and 3-nitrotyrosine. The density and diameter of capillaries were also increased. We conclude that in acute optic neuritis, the optic nerves are hypoxic and come under oxidative and nitrative stress and damage. Tissue hypoxia can cause mitochondrial failure and thus explains visual loss due to axonal conduction block. Tissue hypoxia can also induce a damaging oxidative and nitrative environment. The findings indicate that treatment to prevent tissue hypoxia in acute optic neuritis may help to restore vision and protect from damaging reactive oxygen and nitrogen species. Full article

Sporadic inclusion body myositis (sIBM) is the most common muscle disease of older people and is clinically characterized by slowly progressive asymmetrical muscle weakness, predominantly affecting the quadriceps, deep finger flexors, and foot extensors. At present, there are no enduring treatments for this relentless disease that eventually leads to severe disability and wheelchair dependency. Although sIBM is considered a rare muscle disorder, its prevalence is certainly higher as the disease is often undiagnosed or misdiagnosed. The histopathological phenotype of sIBM muscle biopsy includes muscle fiber degeneration and endomysial lymphocytic infiltrates that mainly consist of cytotoxic CD8⁺ T cells surrounding nonnecrotic muscle fibers expressing MHCI. Muscle fiber degeneration is characterized by vacuolization and the accumulation of congophilic misfolded multi-protein aggregates, mainly in their non-vacuolated cytoplasm. Many players have been identified in sIBM pathogenesis, including environmental factors, autoimmunity, abnormalities of protein transcription and processing, the accumulation of several toxic proteins, the impairment of autophagy and the ubiquitin–proteasome system, oxidative and nitrative stress, endoplasmic reticulum stress, myonuclear degeneration, and mitochondrial dysfunction. Aging has also been proposed as a contributor to the disease. However, the interplay between these processes and the primary event that leads to the coexistence of autoimmune and degenerative changes is still under debate. Here, we outline our current understanding of disease pathogenesis, focusing on degenerative mechanisms, and discuss the possible involvement of aging. Full article

In this review, we delve into the realm of photodynamic therapy (PDT), an established method for combating cancer. The foundation of PDT lies in the activation of a photosensitizing agent using specific wavelengths of light, resulting in the generation of reactive oxygen species (ROS), notably singlet oxygen (¹O₂). We explore PDT’s intricacies, emphasizing its precise targeting of cancer cells while sparing healthy tissue. We examine the pivotal role of singlet oxygen in initiating apoptosis and other cell death pathways, highlighting its potential for minimally invasive cancer treatment. Additionally, we delve into the complex interplay of cellular components, including catalase and NOX1, in defending cancer cells against PDT-induced oxidative and nitrative stress. We unveil an intriguing auto-amplifying mechanism involving secondary singlet oxygen production and catalase inactivation, offering promising avenues for enhancing PDT’s effectiveness. In conclusion, our review unravels PDT’s inner workings and underscores the importance of selective illumination and photosensitizer properties for achieving precision in cancer therapy. The exploration of cellular responses and interactions reveals opportunities for refining and optimizing PDT, which holds significant potential in the ongoing fight against cancer. Full article

Inflammatory bowel disease (IBD) affects millions of people worldwide and is considered a significant risk factor for colorectal cancer. Recent in vivo and in vitro studies reported that ellagic acid (EA) exhibits important antioxidant and anti-inflammatory properties. In this study, we investigated the preventive effects of EA against dextran sulfate sodium (DSS)-induced acute colitis, liver, and brain injury in mice through the gut–liver–brain axis. Acute colitis, liver, and brain injury were induced by treatment with 5% (w/v) DSS in the drinking water for 7 days. Freshly prepared EA (60 mg/kg/day) was orally administered, while control (CON) group mice were treated similarly by daily oral administrations with a vehicle (water). All the mice were euthanized 24 h after the final treatment with EA. The blood, liver, colon, and brain samples were collected for further histological and biochemical analyses. Co-treatment with a physiologically relevant dose (60 mg/kg/day) of EA for 7 days significantly reduced the DSS-induced gut barrier dysfunction; endotoxemia; and inflammatory gut, liver, and brain injury in mice by modulating gut microbiota composition and inhibiting the elevated oxidative and nitrative stress marker proteins. Our results further demonstrated that the preventive effect of EA on the DSS-induced IBD mouse model was mediated by blocking the NF-κB and mitogen-activated protein kinase (MAPK) pathway. Therefore, EA co-treatment significantly attenuated the pro-inflammatory and oxidative stress markers by suppressing the activation of NF-κB/MAPK pathways in gut, liver, and brain injury. These results suggest that EA, effective in attenuating IBD in a mouse model, deserves further consideration as a potential therapeutic for the treatment of inflammatory diseases. Full article

This review focuses on DNA damage caused by a variety of oxidizing, alkylating, and nitrating species, and it may play an important role in the pathophysiology of inflammation, cancer, and degenerative diseases. Infection and chronic inflammation have been recognized as important factors in carcinogenesis. Under inflammatory conditions, reactive oxygen species (ROS) and reactive nitrogen species (RNS) are generated from inflammatory and epithelial cells, and result in the formation of oxidative and nitrative DNA lesions, such as 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) and 8-nitroguanine. Cellular DNA is continuously exposed to a very high level of genotoxic stress caused by physical, chemical, and biological agents, with an estimated 10,000 modifications occurring every hour in the genetic material of each of our cells. This review highlights recent developments in the chemical biology and toxicology of 2′-deoxyribose oxidation products in DNA. Full article

Both β-amyloid (Aβ) peptides and oxidative stress conditions play key roles in Alzheimer’s disease. Hemin contributes to the development of the disease as it possesses redox properties and its level increases in pathological conditions or traumatic brain injuries. The aim of this work was to deepen the investigation of the reactivity of the hemin–Aβ₁₆ complex, considering its ability to catalyze oxidation and nitration reactions. We performed kinetic studies in the presence of hydrogen peroxide and nitrite with phenolic and catechol substrates, as well as mass spectrometry studies to investigate the modifications occurring on the peptide itself. The kinetic constants were similar for oxidation and nitration reactions, and their values suggest that the hemin–Aβ₁₆ complex binds negatively charged substrates with higher affinity. Mass spectrometry studies showed that tyrosine residue is the endogenous target of nitration. Hemin degradation analysis showed that hemin bleaching is only partly prevented by the coordinated peptide. In conclusion, hemin has rich reactivity, both in oxidation and nitration reactions on aromatic substrates, that could contribute to redox equilibrium in neurons. This reactivity is modulated by the coordination of the Aβ₁₆ peptide and is only partly quenched when oxidative and nitrative conditions lead to hemin degradation. Full article

Elucidation of the redox pathways in severe coronavirus disease 2019 (COVID-19) might aid in the treatment and management of the disease. However, the roles of individual reactive oxygen species (ROS) and individual reactive nitrogen species (RNS) in COVID-19 severity have not been studied to date. The main objective of this research was to assess the levels of individual ROS and RNS in the sera of COVID-19 patients. The roles of individual ROS and RNS in COVID-19 severity and their usefulness as potential disease severity biomarkers were also clarified for the first time. The current case-control study enrolled 110 COVID-19-positive patients and 50 healthy controls of both genders. The serum levels of three individual RNS (nitric oxide (NO^•), nitrogen dioxide (ONO⁻), and peroxynitrite (ONOO⁻)) and four ROS (superoxide anion (O₂^•−), hydroxyl radical (^•OH), singlet oxygen (¹O₂), and hydrogen peroxide (H₂O₂)) were measured. All subjects underwent thorough clinical and routine laboratory evaluations. The main biochemical markers for disease severity were measured and correlated with the ROS and RNS levels, and they included tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), the neutrophil-to-lymphocyte ratio (NLR), and angiotensin-converting enzyme 2 (ACE2). The results indicated that the serum levels of individual ROS and RNS were significantly higher in COVID-19 patients than in healthy subjects. The correlations between the serum levels of ROS and RNS and the biochemical markers ranged from moderate to very strongly positive. Moreover, significantly elevated serum levels of ROS and RNS were observed in intensive care unit (ICU) patients compared with non-ICU patients. Thus, ROS and RNS concentrations in serum can be used as biomarkers to track the prognosis of COVID-19. This investigation demonstrated that oxidative and nitrative stress play a role in the etiology of COVID-19 and contribute to disease severity; thus, ROS and RNS are probable innovative targets in COVID-19 therapeutics. Full article

Nitric oxide (NO) and carbon monoxide (CO) represent a pair of biologically active gases with an increasingly well-defined range of effects on circulating platelets. These gases interact with platelets and cells in the vessels and heart and exert fundamentally similar biological effects, albeit through different mechanisms and with some peculiarity. Within the cardiovascular system, for example, the gases are predominantly vasodilators and exert antiaggregatory effects, and are protective against damage in myocardial ischemia-reperfusion injury. Indeed, NO is an important vasodilator acting on vascular smooth muscle and is able to inhibit platelet activation. NO reacts with superoxide anion (O₂(⁻•)) to form peroxynitrite (ONOO(⁻)), a nitrosating agent capable of inducing oxidative/nitrative signaling and stress both at cardiovascular, platelet, and plasma levels. CO reduces platelet reactivity, therefore it is an anticoagulant, but it also has some cardioprotective and procoagulant properties. This review article summarizes current knowledge on the platelets and roles of gas mediators (NO, and CO) in cardioprotection. In particular, we aim to examine the link and interactions between platelets, NO, and CO and cardioprotective pathways. Full article

Oxidative stress, neurodegeneration, neuroinflammation, and vascular leakage are believed to play a key role in the early stage of diabetic retinopathy (ESDR). The aim of this study was to investigate the blockade of cannabinoid receptor 1 (CB1R) and activation of cannabinoid receptor 2 (CB2R) as putative therapeutics for the treatment of the early toxic events in DR. Diabetic rats [streptozotocin (STZ)-induced] were treated topically (20 μL, 10 mg/mL), once daily for fourteen days (early stage DR model), with SR141716 (CB1R antagonist), AM1710 (CB2R agonist), and the dual treatment SR141716/AM1710. Immunohistochemical-histological, ELISA, and Evans-Blue analyses were performed to assess the neuroprotective and vasculoprotective properties of the pharmacological treatments on diabetes-induced retinal toxicity. Activation of CB2R or blockade of CB1R, as well as the dual treatment, attenuated the nitrative stress induced by diabetes. Both single treatments protected neural elements (e.g., RGC axons) and reduced vascular leakage. AM1710 alone reversed all toxic insults. These findings provide new knowledge regarding the differential efficacies of the cannabinoids, when administered topically, in the treatment of ESDR. Cannabinoid neuroprotection of the diabetic retina in ESDR may prove therapeutic in delaying the development of the advanced stage of the disease. Full article